Sea-Floor Spreading

Front

_______ are mountain ranges at the bottom of the ocean.

Back

Mid-ocean ridges

Front

The mid-ocean ridges are sites of intense _________ activity.

Back

volcanic

Front

At the mid-ocean ridge, molten rock rises through the cracks in _________.

Back

the seafloor

Front

When molten rocks cool and solidify, they form new ________.

Back

crust

Front

___________ is the process through which new oceanic lithosphere (seafloor) is formed as magma rises to the Earth's surface and solidifies at the mid-ocean ridge.

Back

Seafloor spreading

Front

___________ is the hypothesis that states that the continents were once a single landmass, then broke apart and drifted to their current locations.

Back

Continental Drift

Front

In the 1960s, scientists studying the ocean floor discovered _____________.

Back

That the ocean floor contains magnetic patterns

Front

Throughout Earth's history, the magnetic north and south poles have switched places several times.

Back

True

Front

The oceanic crust near the mid-ocean ridge is younger than the oceanic crust farther from the ridge.

Back

True

Front

What technology did scientists use in the mid-20th century to map the mid-ocean ridge?

Back

Sonar